There is a strong need for conformal antennas. Conformal antennas are located very close to a surface, typically a small fraction of a wavelength. Usually, this surface is made of conductive metal. One example of a conductive metal surface is the outer skin of an aircraft, where a conformal antenna would be placed. The conformal shape of the antenna permits it to operate without disturbing the aerodynamics of the aircraft.
Conformal antenna design is limited by the conducting ground plane. A conducting surface tends to reduce the RF electromagnetic fields transmitted or received by any antenna placed close to and oriented tangentially to it. Another way to understand this is to replace the infinite perfect conductor with an image antenna. The two antennas will constructively interfere if the spacing is one-half a wavelength. If the spacing is a small fraction of a wavelength, the radiation destructively interferes, due to the fact that when the waves are reflected from the ground plane they undergo a 180 degree phase shift. Thus, if the distance between the antenna element and ground plane is a small fraction of a wavelength, the waves coming directly from the antenna element and those reflected from the ground plane will nearly cancel. A need exists for a conformal antenna that prevents the cancellation of waves coming directly from the antenna element.